1. Field of the Invention
The present invention relates to fixing devices, particularly to a fixing device in which a heating section is provided in a heating roller.
2. Description of Related Art
As an invention relevant to a conventional fixing device, for example, a fixing device described in Japanese Laid-Open Patent Publication No. 2013-3190 is known. This fixing device includes a heating roller, a fixing roller, a heater, and a fixing belt. The heating roller and the fixing roller are arranged parallel to each other. The fixing belt is stretched between the heating roller and the fixing roller. The heater is provided in the heating roller so as to heat the heating roller.
To put the fixing belt and the heating roller in tight contact, the fixing device as above has a structure to be descried below. The heating roller is configured so as to be slidable with respect to the fixing roller in a direction perpendicular to an axial direction of the heating roller. Further, the heating roller receives a force from an elastic object, such as a spring, in a direction away from the fixing roller. This puts the fixing belt in tight contact with the heating roller without slackening. As a result, heat from the heating roller is efficiently transferred to the fixing belt.
Incidentally, as for the above fixing device, there is difficulty in reducing the diameter of the heating roller. More specifically, the fixing device is configured in such a manner as to allow the heating roller to slide with respect to the fixing roller. However, the heating roller has the heater provided therein, and the heater is not slidable with respect to the fixing roller. Accordingly, if the diameter of the heating roller is reduced excessively, the heater might hit the inner circumferential surface of the heating roller when the heating roller slides.